Conventionally, this type of printing apparatus prints a predetermined image pattern on a fabric set on a setting surface on which a printing medium is set by moving a carriage equipped with an ink head using the ink jet method, horizontally to the setting surface.
Concretely, the carriage is supported on a carriage beam in a manner enabling it to reciprocate, and the carriage beam is supported on the printer body having the setting surface in a manner enabling the carriage beam to reciprocate in the direction orthogonal to the carriage moving direction.
Then, a control device for controlling the driving of the carriage beam, the carriage, and the ink head is provided, image data of images of a-pattern to be printed on a fabric is recorded in advance on the control device, and when printing, ink is discharged from the nozzle of the ink head according to the image data to print the predetermined image on the surface of a fabric.
The ink head of the ink jet printing apparatus has eight unit heads for individually discharging of ink in dark and light colors of four colors including, for example, yellow, magenta, cyan, and black, that is, ink of eight colors.
Then, when printing, an ink necessary for printing is selected in these eight unit heads and the determined ink is discharged from the nozzle of the selected unit head.
Since an ink of a predetermined unit head is selected when printing, depending on the image to be printed, the time interval from discharge to the next discharge from the unit heads may become longer, and as a result, ink discharge may not be carried out for a definite period of time or more. In this case, ink adhering to the nozzle is dried and the discharge opening of the nozzle is clogged.
Therefore, in the ink jet printing apparatus described above, in order to prevent the nozzle of the ink head from being clogged, for example, it is common that flushing to forcibly discharge the ink from the nozzle of the ink head is carried out when a predetermined period of time elapses from the start of execution of the printing processing.
Then, in the case where flushing is carried out in the conventional ink jet printing apparatus, the carriage with the ink head is moved to a non-printing region outside a moving region for printing an image, and the nozzle of the ink head is moved closer to an ink recovery tank that is disposed in the non-printing region, and thereafter, a predetermined amount of ink is discharged from the opening of the nozzle into the ink recovery tank.
However, in the above-described printing apparatus, when flushing is carried out during the printing processing, as mentioned above, the carriage must be moved to the non-printing region outside the moving region for printing, and after the flushing is finished, the carriage must be returned to the printing region again, and this results in a lengthened printing time in total.
On the other hand, in order to solve the above-described problem, for example, a printing apparatus is disclosed in Japanese Published Unexamined Patent Application No. H09-11502, wherein the ink recovery tank for the ink discharged from the nozzle of the ink head is installed in the apparatus main body together with the carriage with the ink head, and the carriage is supported onto the apparatus main body in a manner enabling it to freely swing.
In this printing apparatus, the ink recovery tank is fixed at a position apart from the printing object setting surface that is to be regarded as a printing position in the apparatus main body, and the carriage is supported onto the apparatus main body in a manner enabling it to swing so that the nozzle of the ink head can be moved to the printing position and a position opposite the ink recovery tank.
During image printing, the nozzle of the ink head is positioned at the printing position, and in the middle of image printing, when a predetermined period of time elapses in regard to an unused unit head, the nozzle of the ink head is swung to the position opposite the ink recovery tank for flushing the ink and a predetermined amount of ink is discharged from the nozzle into the ink recovery tank.
However, in the above-described carriage swing type printing apparatus, although the problem that lengthens the period of time required for printing is solved, if the printing area is increased as in the case of a printing apparatus for printing onto a fabric, the ink supply amount must be increased and this inevitably makes the carriage large, so that a large space is required for swinging the carriage.
Particularly, when it is demanded that the ink types are increased and the number of unit heads of the ink head is increased, the carriage becomes larger, so that the swinging space cannot be secured and the number of unit heads cannot be increased.
In addition, when the large-sized carriage is swung, the distance from its pivot to the center of gravity lengthens, so that the swinging mechanism for swinging the heavy carriage against the gravitational force is also increased in size for obtaining strength to withstand the swinging motion, and as a result, the entirety of the printing apparatus is increased in size.
The present invention has been developed in view of the above-described circumstances, and an object thereof is to provide a printing apparatus which can carry out flushing of ink at a predetermined timing even when an ink head is positioned at an arbitrary position above a printing object without an increase in size of the printing apparatus and without an increase in total time required for printing.